There are a range of risk factors associated with higher rates of illness or injury in the population. Such factors may be physiological (e.g. high blood pressure), they may relate to the environment (e.g. air pollution) or to lifestyle choices (e.g. smoking). Risk factors have been found to contribute substantially to disease and disability, and thus to reduced length of life and quality of life in Australia (Mathers et al. 1999). However, many risk factors are modifiable. Their impact may often be reduced through action taken by individuals (e.g. quitting smoking or undertaking exercise). In turn, these actions may be influenced by government or community action (e.g. anti-smoking education).

This article focuses on four risk factors: smoking; physical inactivity; overweight and obesity; and risky/high risk alcohol consumption. While each of these is discussed individually, they interact with other risk factors, and are rarely the sole contributor to a disease (WHO 2000).

Data in this article come from the Australian Bureau of Statistics (ABS) 2001 National Health Survey (NHS). In this article, the data refer to adults aged 18 years and over. Definitions or more precise descriptions of terms used in this article, such as 'current smokers', 'physical inactivity', 'overweight and obesity', and risky/high risk alcohol consumption' can be found in 'Health risk factors among adults' Australian Social Trends, 2003 (4102.0). Data on risk factors exhibited by Aboriginal and Torres Strait Islander peoples come from the Indigenous component of the 2001 NHS.

Smoking

Worldwide, smoking is estimated to cause almost five million premature deaths each year (WHO 2002). In Australia, it is estimated that around 19,000 people died as a result of smoking in 1998 (Riddolfo & Stevenson 2001). Among other conditions, smoking is associated with increased risk of coronary heart disease, stroke, lung cancer, other types of cancer and various respiratory and cardiovascular diseases (WHO 2000). In 2001, people aged 18 years and over who currently smoked were 2.0 times more likely to have bronchitis and were 1.7 times more likely to have emphysema compared with non-smokers. In relation to other conditions such as coronary heart disease, there was little difference between current smokers and people who had never smoked. However, current smokers combined with ex-smokerswere 1.4 times more likely to have coronary heart disease and were 1.7 times more likely to have a malignant cancer than those who had never smoked. These higher disease rates - apparent once ex-smokers are included - suggest that certain health conditions may be associated not only with current smoking but with a history of smoking.

In 2001, 24% of the adult population were current smokers. Smoking was highest among 25-34 year olds (32%), and people were less likely to smoke as they reached older age groups (graph S9.11). This is partly because smoking is associated with higher premature death rates, and smokers are less likely to live to the older age groups.

Men were more likely to smoke than women (28% and 21% respectively). Men were also more likely to smoke over all age categories than women, with the greatest disparity being among those in younger age groups. For 25-34 year olds (the age group with the highest rate of smoking) 37% of men and 28% of women were current smokers.

Adults from the most disadvantaged socioeconomic areas were more likely to smoke than adults from each of the other four socioeconomic areas (graph S9.12). (For a description of the five socioeconomic areas see Socio-Economic Indexes for Areas (SEIFA) in (ABS 1998b).) Adults without a tertiary education were more than twice as likely to smoke (28% in 2001) compared with those with a tertiary qualification (13%). Smoking was also more prevalent among the unemployed. In 2001, 40% of unemployed adults aged 18-64 years smoked compared with 26% of people aged 18-64 years who were employed.

Physical inactivity

The health benefits of engaging in physical activity are numerous, such as offering protection against some cancers, a reduction in the risk of diabetes and cardiovascular disease and improvements in mental health (Armstrong et al. 2000). Physical activity may also reduce the risk of injury among older people (Armstrong et al. 2000), reduce body fat and improve musculoskeletal health (WHO 2002). Conversely, physical inactivity increases the risk of developing some cancers such as bowel and breast cancer, coronary heart disease, Type 2 diabetes and depression, among other conditions (Mathers et al. 1999). In 2001, physically inactive adults were 1.3 times more likely to have coronary heart disease, and 1.2 times more likely to be obese, than those who exercised. This difference was more evident when comparing inactive adults with those who exercised at moderate or high (rather than low) levels. In this case, physically inactive adults were 1.6 times more likely to be obese and 1.7 times more likely to have a high or very high level of psychological distress.

In 2001, 32% of the adult population were physically inactive (i.e. they did not undertake deliberate exercise, or did so at a very low level, during the survey reference period). When asked to rate their health, 74% of physically inactive adults considered their health to be better than fair, compared with 81% of the total adult population.

In 2001, similar proportions of men and women were physically inactive (31% and 32% respectively). However, men were more likely to exercise at a moderate level (26%) than women (23%), and to exercise at a high level (9%) compared with women (4%).

Physical inactivity was highest among people in older age groups with 35% of those between 65-74 years, and 51% of those over 75 years being physically inactive. Of adults aged 45-54 years, 32% were physically inactive. Males were more likely to be physically inactive than females after the age of 25 years and until retirement age (graph S9.13). Lower proportions of males than females were physically inactive between the ages of 18-24 years and among those over 65 years.

Physical inactivity was more common among adults from the more disadvantaged socioeconomic areas (graph S9.14). Among adults from the most disadvantaged socioeconomic areas, 40% were physically inactive compared with 25% of adults from the least disadvantaged socioeconomic areas.

Overweight and obesity

The proportion of people who are either overweight or obese is increasing worldwide (WHO 2000), and despite decreases in the proportion of people who are physically inactive, Australians are also carrying more excess weight. The World Health Organisation recognises that globally there was a decrease in the physical energy people expend in everyday living over the second half of the 20th century (WHO 2000). For example, there is more reliance on motorised transport, and use of labour-saving devices. Changes in the workplace, such as increased use of computers, mean that fewer people now work in physically demanding jobs. Furthermore, there is increased demand for convenience foods which are higher in fat (especially saturated fat) (WHO 2000). People are also more likely now than in the past to participate in leisure activities which involve little, if any, physical activity, such as watching television. In 1997, on average, Australians spent more than half of their free time on such passive leisure activities. Watching television accounted for 36% of all free time (ABS 1998a).

Being overweight or obese is associated with a range of illnesses including coronary heart disease, Type 2 diabetes, certain types of cancer, gallbladder disease, osteoarthritis and high blood pressure (WHO 2000). Compared with adults within the acceptable weight range (according to the Body Mass Index - BMI), persons aged 18 years and over who were overweight or obese were 1.9 times more likely to have Type 2 diabetes and were 1.6 times more likely to have high blood pressure in 2001. The likelihood increased among those adults who were obese. This group was 2.9 times more likely to have Type 2 diabetes, 2.2 times more likely to have high blood pressure, and 1.5 times more likely to have a form of arthritis.

In 2001, more than 6.5 million Australian adults were overweight or obese. Men were more likely to be overweight or obese than women (55% and 38% respectively), with the average weight of Australians being 74.3 kilograms. The proportion of adults who were overweight or obese tended to increase with age, peaking among those aged 55-64 years (59%). This was the case among both males and females (64% and 53% respectively).

Men were more likely to be overweight than women (40% and 23% respectively). The prevalence of men being overweight was highest among those aged between 55-64 years (47%), while women between the ages of 65-74 years were most likely to be overweight (32%).

However, women were slightly more likely to be obese than men. Men between 45-54 years had the highest prevalence of obesity (19%), while women aged between 55-64 years were most likely to be obese (22%) (graph S9.15).

The prevalence of overweight or obesity is higher among certain groups in the population than others. In 2001, 45% of people in the most disadvantaged socioeconomic areas were overweight or obese compared with 43% in the least disadvantaged socioeconomic areas (graph S9.16). However, people in the middle socioeconomic areas (3rd SEIFA quintile) were most likely to be overweight or obese (49%). Among people who were overweight, 34% of men and 21% of women from the most disadvantaged socioeconomic areas were overweight compared with 39% of men and 23% of women from the least disadvantaged socioeconomic areas. Conversely, there was a higher prevalence of obesity among people from the most disadvantaged socioeconomic areas (18% of men and 19% of women) than among people from the least disadvantaged socioeconomic areas (12% of men and 11% of women). Adults living outside of capital cities were also more likely to be overweight or obese (49%) than those in the capital cities (45%).

Risky or high risk alcohol consumption

Despite evidence indicating low to moderate levels of alcohol consumption may protect against some conditions such as hypertension, stroke and ischaemic heart disease, consumption at harmful levels can be directly associated with some cancers, liver disease, pancreatitis, diabetes and epilepsy, and indirectly linked to injuries such as through motor vehicle accidents. In 1998, estimated deaths in Australia attributable to the consumption of alcohol was 3,200 (AIHW 2001a). Recent decades have witnessed a global increase in alcohol consumption, with developing countries being the major contributors. In average volume terms, Europeans and North Americans have the highest consumption, with the Eastern Mediterranean, India, Bangladesh and Nepal being among the lowest (WHO 2002). In 1998, Australia was ranked 19th for per capita alcohol consumption; 9th for beer; 18th for wine and 35th for spirits (AIHW 2001a). In the 2001 NHS, 62% of adults recorded that they consumed alcohol in the reference week, and a further 28% recorded consuming alcohol, but not in the reference week.

In 2001, 1.5 million Australian adults (11%) consumed alcohol in risky or high risk amounts. Levels of risky or high risk alcohol consumption was generally constant between the ages of 18-64 years (around 11%), only decreasing after the age of 65 years. Men were more likely to consume alcohol in risky or high risk amounts (13%) compared to women (9%). Risky or high risk alcohol consumption was most prevalent for men between the ages of 55-64 years (15%), while women were most likely to consume alcohol in risky or high risk amounts at younger ages, with 10% of women between the ages of 35-54 years consuming alcohol at this risk level (graph S9.17).

The consumption of alcohol at risky or high risk levels differed among certain socioeconomic groups. Overall, people in the least disadvantaged socioeconomic areas were most likely to consume alcohol at risky or high risk levels (12%). In comparison, the proportion of people in the most disadvantaged socioeconomic areas (graph S9.18) who consumed alcohol in risky or high risk amounts was slightly less (11%). However, men in the most disadvantaged socioeconomic areas were more likely to consume alcohol in risky or high risk amounts than those in the least disadvantaged socioeconomic areas (14% and 12% respectively). Women in the most disadvantaged socioeconomic areas were less likely to consume alcohol in risky or high risk amounts than those in the least disadvantaged socioeconomic areas (8% and 11% respectively).

Since the Indigenous population has a different age structure to the non-Indigenous population, comparisons in health risk behaviour are presented after adjusting for the differences in age structure between the two populations.

Smoking

Indigenous adults aged 18 years or more were more than twice as likely as non-Indigenous adults to be current smokers (49% compared with 22%). Rates of smoking are similar for both females and males.

Sedentary or low levels of exercise

Around 70% of both Indigenous and non-Indigenous adults living in non-remote areas in 2001 reported their levels of exercise as either sedentary or low in the two weeks prior to being surveyed, with proportions generally increasing with age. A higher proportion of Indigenous women reported undertaking low or sedentary levels of exercise than Indigenous men (64% and 50% respectively).

Overweight or obesity

Body mass categories discussed in this paragraph are based on self reported measurements of height and weight. Indigenous Australians aged 15 years or more were more likely (61%) to be classified as overweight or obese when compared with non-Indigenous Australians (48%). The proportion of both Indigenous and non-Indigenous persons, aged 18 years or more and classified as obese, has increased since 1995. Indigenous men and women in each age group were more likely to be classified as obese than non-Indigenous Australians in the same age groupings. Proportions of both Indigenous men and women who were overweight or obese generally increased towards older age groups.

Risky or high risk alcohol consumption

The age-standardised rates for risky/high risk levels of alcohol consumption for the week preceding the 2001 NHS were similar for both the Indigenous and non-Indigenous populations (12% and 11% respectively).